Surgical anatomy, technique and application of endoscopic endonasal transpterygoid approach in skull base surgery

Abstract

To identify the landmarks of transpterygoid approach and to report its application in a series of cases. Two silicon-injected adult cadaveric heads(4 sides) were dissected by performing an endoscopic endonasal transpterygoid approach after CT scanning for imaging guidance. High-quality pictures were obtained. This approach was used to treat twelve patients with skull base lesions including 3 spontaneous cerebrospinal fluid (CSF) leaks in the lateral recess of the sphenoid sinus, 2 neurofibromas and 2 Schwannomas involving the pterygopalatine fossa and infratemporal fossa, 1 dermoid cyst involving the middle fossa and infratemporal fossa, 1 invasive fungal sinusitis invading the middle fossa base, 1 basal cell adenoma in the upper parapharyngeal space, 1 chondrosarcoma in the parasellar region and 1 adenoid cystic carcinoma. Clinical records were reviewed. In terms of approach dissection, important landmarks, such as the sphenopalatine foramen and artery, vidian canal and nerve, foramen rotundum and maxillary branch of trigeminal nerve, foramen ovale and mandibular branch of trigeminal nerve, as well as pterygoid segment of Eustachian tube were identified. In terms of clinical data, three patients with spontaneous CSF leak underwent repair. Six patients with benign lesions underwent complete tumor resection. In the patient with invasive fungal disease, thorough debridement was undertaken and antifungal drug was administered for one month. For these benign skull base lesions, there was no recurrence during the follow-up period. In the patient with chondrosarcoma, most of the tumor was removed in the first operation, and was followed by two endoscopic operations because of fast growth of the tumor. Final control was achieved with chemotherapy and radiation. In the patient with adenoid cystic carcinoma, tumor recurred five years after surgery, and was reoperated. An understanding of the landmarks of the transpterygoid approach is paramount for surgically dealing with disease located within and adjacent to the region of the pterygoid process of the sphenoid bone. The endoscopic endonasal transpterygoid approach is feasible and safe in selected patients with skull base lesions.